Theme 4: Poster Abstract
Experimental Stocking Trials Off Portugal's Southern Coast
Pedro Gil Lino, Miguel Neves dos Santos, Pedro Pousão-Ferreira and Carlos Costa Monteiro
INIAP – IPIMAR, Avenida 5 de Outubro S/N, 8700-305 Olhão, Portugal
plino@cripsul.ipimar.pt
Downloadable Abstract
The decline in the catch of commercially important local species concerns fisheries managers in Portugal. Consequently, policies promoting sustainable exploitation of local fisheries have been implemented, together with the development of new aquaculture products. IPIMAR (Portuguese Marine and Fisheries Research Institute) has been particularly involved in the development of new management tools such as restocking.
Since 1997, IPIMAR has done experimental releases of tagged seabreams (Sparidae: Sparus aurata, Diplodus sargus, D. cervinus and D. vulgaris) and sole (Solea senegalensis) into the Algarve coastal waters (southern Portugal). These specimens have been produced at the Institute's hatchery facility. The objective was to minimize costs and maximize survival by determining the ideal size, location, and timing for release.
The short average distance of recaptured fish from the release point with time showed that these species tend to seek refugia and to adapt to local habitats. Preliminary results suggest that S. aurata, D. sargus and D. cervinus appear to be good candidates for restocking at the regional level. Gut content analyses also indicate fast adaptation to self feeding on live prey. Behavioral observations showed that after an initial adaptation, the released fish tend to school with wild fish of the same size and species. The preliminary results also show that some adaptation to predators is required before release. As the trials with D. vulgaris and S. senegalensis specimens are recent, the results are still limited and inconclusive.
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